weights = torch.tensor([0.5,0.5])# 假设的一维数据集data = torch.cat((torch.randn(100) *1.5, torch.randn(100) *0.5+5))# EM算法实现foriterationinrange(100):# E步骤posterior_probabilities = []foriinrange(2): normal_distribution = Normal(means[i], torch.sqrt(variances[i])) posterior_...
和EM算法一样,K-means每一步都最小化目标函数JJ,因而可以保证收敛到局部最优值,但在非凸目标函数的情况下不能保证收敛到全局最优值。另外,K-means对每个样本进行“硬分配(hard assignment)”,即只归类为一个簇,然而某些样本可能处于簇与簇的边界处,将这些样本强行分到其中一个簇可能并不能反映确信度。后文的...
是未知的,称为隐变量,如无监督的学习问题,典型的如K-Means聚类算法,此时不能直接通过极大似然估计估计出模型中的参数。 二、EM算法简介 在上述存在隐变量的问题中,不能直接通过极大似然估计求出模型中的参数,EM算法是一种解决存在隐含变量优化问题的有效方法。EM算法是期望极大(Expectation Maximization)算法的简称,...
# 计算隐变量分布的参数估计值forkinrange(n_gauss):alpha[k]=(np.sum(q[:,k])/total) k-means算法与GMM模型的关系 在前面我们曾提到, k-means 算法是GMM模型的一个变种, 那具体这二者之间是一个怎么样的关系呢? 为了回答这个问题, 我们需要先对GMM模型做几个限制: 1.不完全数据 中的每个样本将不再...
Swing around enemies, hide in the dark, jump through space and time, rotate with the environment, and avoid tricky obstacles. Each stage is carefully introduced, gradually advanced, and twisted into countless exciting variations. Be in Control (Accessibility) ...
{ "test_page": [ "unit-tests.html", "integration-tests.html" ] } This will cause Testem to run each test page in a separate launcher instance for each launcher you are using. This means that if you define 2 test pages and are using 3 launchers you will get 6 unique runs (2 pe...
This means you can technically output in CommonJS to get ESM and CommonJS support. require()in ESM Sometimes it's useful to userequire()orrequire.resolve()in ESM. ESM code that usesrequire()can be seamlessly compiled to CommonJS, but when compiling to ESM, Node.js will error becauserequi...
Computer dictionary definition for what em dash means including related links, information, and terms.
When used in a text, EM means "Them (often 'EM)". While this is its most common meaning in texting, be aware that it is a rare term, and it might mean something else. If our meaning does not fit, give the context of your conversation a name (e.g., love, sport, space, astron...
3. Finally, "em-" can also indicate "from somewhere or something," preceding prepositions to denote the origin or source of something or someone. For example, "emigrate" means "to leave one's country and settle in another," and "employ" means "to hire someone from a company ...